Benchmark: for vs array.foreach vs for..in vs for..of

Script Preparation code:

var array = new Array(1000);

Tests:

for
for (var i = 0; i < array.length; i++) { array[i]; }
foreach
array.forEach((i) => { array[i]; });
for in
for (var i in array) { array[i]; }
for..of
for (var i of array) { array[i]; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
for
foreach
for in
for..of

Fastest: N/A

Slowest: N/A

Latest run results:

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Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):

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Let's break down the provided benchmark definition and test cases.

**Benchmark Definition:**
The benchmark is designed to compare the performance of four different loop types in JavaScript:

1. Traditional `for` loop
2. Array method `forEach`
3. `for...in` loop (which iterates over the object's own enumerable properties)
4. `for...of` loop (introduced in ECMAScript 2015, also known as "spread operator for" loops)

**Script Preparation Code:**
The script creates an array of length 1000 using `new Array(1000)`. This array will be used to test the different loop types.

**Html Preparation Code:**
There is no HTML preparation code provided, which means that the benchmark is executed in a headless browser or a JavaScript environment without a graphical interface.

Now, let's examine each individual test case:

1. **Traditional `for` loop:**
	* Purpose: To measure the performance of a traditional `for` loop.
	* Pros: Simple and widely supported; can be used for other types of loops as well.
	* Cons: May have additional overhead due to the need to manage the loop variable (`i`) explicitly.
2. **Array method `forEach`:**
	* Library: The `forEach` method is a part of the ECMAScript standard, which means it's a built-in JavaScript function.
	* Purpose: To measure the performance of using `forEach` to iterate over an array.
	* Pros: Efficient and concise; eliminates the need to manage loop variables explicitly.
	* Cons: May not be supported in older browsers or environments that don't implement the ECMAScript standard.
3. **`for...in` loop:**
	* Library: The `for...in` loop is a part of the ECMAScript standard, which means it's a built-in JavaScript construct.
	* Purpose: To measure the performance of using `for...in` to iterate over an array.
	* Pros: Wide support across browsers and environments; can be used for other types of objects as well.
	* Cons: May not be suitable for iterating over arrays, which have no inherent ordering or property names.
4. **`for...of` loop:**
	* Library: The `for...of` loop is a part of the ECMAScript 2015 standard (ES6+), which means it's supported in modern browsers and environments.
	* Purpose: To measure the performance of using `for...of` to iterate over an array.
	* Pros: Efficient and concise; eliminates the need to manage loop variables explicitly.
	* Cons: May not be supported in older browsers or environments that don't implement ES6+.

**Other Alternatives:**

In addition to these four loop types, there are other ways to iterate over arrays in JavaScript, such as:

* `while` loops
* `do...while` loops
* Using functions with callback arguments (e.g., `array.map()`, `array.filter()`)

These alternatives may have different performance characteristics and trade-offs compared to the four loop types mentioned above.

In summary, the provided benchmark definition is designed to compare the performance of four different loop types in JavaScript: traditional `for` loops, array method `forEach`, `for...in` loops, and `for...of` loops. The test cases use an array of length 1000 as a sample dataset, and the results can be used to compare the performance of these loop types across different browsers and environments.

Related benchmarks:

for vs array.foreach vs for..in vs for..of (version: 0)

Compare loop performance

Comparing performance of: for vs foreach vs for in vs for..of

Created: 2 years ago by: Guest

Jump to the latest result

for

foreach

for in

for..of

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

No previous run results

Autogenerated LLM Summary (model llama3.2:3b, generated one year ago):